An eight-week, multicentric, randomized, interventional, open-label, phase 4, parallel comparison of the efficacy and tolerability of the fixed combination of timolol maleate 0.5%/brimonidine tartrate 0.2% versus fixed combination of timolol maleate 0.5%/dorzolamide 2% in patients with elevated intraocular pressure.

PURPOSE

To compare the efficacy and tolerability of the fixed combination of timolol maleate 0.5%/brimonidine tartrate 0.2% versus fixed combination of timolol maleate 0.5%/dorzolamide 2% in patients with elevated intraocular pressure (IOP) over 8 weeks.

PATIENTS AND METHODS

This 8-week, multicentric, interventional, randomized, open-label, parallel group study was conducted at 4 centers in Brazil and 1 center in Argentina. Patients with open-angle glaucoma or ocular hypertension were randomized to receive bilaterally fixed combination of brimonidine/timolol maleate 0.5% or fixed combination of dorzolamide 2%/timolol 0.5% twice daily at 8:00 AM and 8:00 PM. A modified diurnal tension curve (8:00 AM, 10:30 AM, 02:00 PM, and 4:00 PM) followed by the water drinking test (WDT), which estimates IOP peak of diurnal tension curve, were performed in the baseline and week-8 visits. Adverse events data were recorded at each visit.

RESULTS

A total of 210 patients were randomized (brimonidine/timolol, n=111; dorzolamide/timolol, n=99). Mean baseline IOP was 23.43+/-3.22 mm Hg and 23.43+/-4.06 mm Hg in the patients treated with brimonidine/timolol and dorzolamide/timolol, respectively (P=0.993). Mean diurnal IOP reduction after 8 weeks were 7.02+/-3.06 mm Hg and 6.91+/-3.67 mm Hg, respectively (P=0.811). The adjusted difference between groups (analysis of covariance) at week 8 was not statistically significant (P=0.847). Mean baseline WDT peak was 27.79+/-4.29 mm Hg in the brimonidine/timolol group and 27.68+/-5.46 mm Hg in the dorzolamide/timolol group. After 8 weeks of treatment, mean WDT peaks were 20.94+/-3.76 mm Hg (P<0.001) and 20.98+/-4.19 (P<0.001), respectively. The adjusted difference between groups (analysis of covariance) was not statistically significant (P=0.469). No statistical difference in terms of adverse events was found between groups.

CONCLUSIONS

Both fixed combinations were capable of significantly reducing the mean diurnal IOP, mean diurnal peak, and mean WDT peak after 8 weeks of treatment. Also, both fixed combinations are well tolerated with few side effects.